US7535651B2 - Zoom lens and image pickup apparatus having the same - Google Patents

Zoom lens and image pickup apparatus having the same Download PDF

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US7535651B2
US7535651B2 US11/846,412 US84641207A US7535651B2 US 7535651 B2 US7535651 B2 US 7535651B2 US 84641207 A US84641207 A US 84641207A US 7535651 B2 US7535651 B2 US 7535651B2
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lens
zoom lens
lens unit
refractive power
zoom
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US20090009883A1 (en
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Ken Wada
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Canon Inc
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Canon Inc
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/177—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a negative front lens or group of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
    • G02B15/1435—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative
    • G02B15/143507—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being negative arranged -++
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/22—Telecentric objectives or lens systems

Definitions

  • the present invention relates to a zoom lens and an image pickup apparatus having the zoom lens, and more particularly, though not exclusively, a zoom lens that can be used, for example, in an image pickup apparatus.
  • the market has desired a highly functional and small-sized image pickup apparatus (camera), such as a video camera or a digital still camera. Furthermore, the market has also desired a small optical system (imaging optical system), which is used in such a camera, having a wide angle of view and a large aperture, with a small number of lenses, and having a high optical performance.
  • a small optical system imaging optical system
  • a camera using an image sensor includes a low-pass filter and a color collection filter disposed between a rearmost lens portion and the image sensor. Accordingly, it is required that a zoom lens for use with such a camera has a relatively long back focal length.
  • a zoom lens for use with such a camera is telecentric on the image side.
  • a so-called retro focus type zoom lens having a front lens unit having a negative refractive power and a rear lens unit having a positive refractive power in order from the object side to the image side is known as a zoom lens that is telecentric on the image side.
  • U.S. Pat. Nos. 6,545,819 and 6,498,687 each discuss a three-unit zoom lens including a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power in order from the object side to the image side.
  • U.S. Pat. No. 5,009,491 and U.S. Patent Application Publication No. US 2004/0150890 A1 each discuss a three-unit zoom lens capable of correcting various aberrations occurring due to a high zoom ratio with a third lens unit.
  • Japanese Patent Application Laid-Open No. 2004-318104 and U.S. Pat. No. 7,042,651 each discuss a small-size three-unit zoom lens having a first lens unit including two lens elements.
  • the method for both implementing the downsizing of a camera and increasing the zoom ratio includes a so-called lens retraction method.
  • the interval between lens units in a non-photographing state is reduced to an interval that is different from the interval in a photographing state so as to reduce the amount of protrusion of the lens from the camera body.
  • each lens unit that constitutes a zoom lens As the number of lens elements of each lens unit that constitutes a zoom lens is large, the length of each lens unit along an optical axis becomes large and, thus, the entire length of the zoom lens becomes large. In addition, when the amount of movement of each lens unit during zooming or focusing is large, the entire length of the zoom lens becomes large. As a result, a desired length of the zoom lens with the lens units retracted cannot be obtained. Accordingly, it becomes difficult to utilize the lens retraction method. That is, as the zoom ratio of a zoom lens becomes higher, the entire length of the zoom lens becomes larger, and accordingly, it becomes difficult to apply the lens retraction method.
  • the number of lenses in the entire optical system can be reduced often by using a lens having an aspheric surface.
  • aberrations related to the monochromatic image forming performance can be corrected, but it is difficult to correct or reduce chromatic aberration occurring mainly due to selection of a glass material.
  • the present invention is directed to a zoom lens that can be used in an image pickup apparatus (e.g., a digital still camera, a video camera, a film camera, and other image pickup apparatuses as known by one of ordinary skill in the relevant arts).
  • an image pickup apparatus e.g., a digital still camera, a video camera, a film camera, and other image pickup apparatuses as known by one of ordinary skill in the relevant arts.
  • the present invention is directed to a zoom lens whose number of constituent lenses is small, whose lens total length is short, and whose various aberrations (e.g., chromatic aberration) are appropriately corrected or reduced, and to an image pickup apparatus having the zoom lens.
  • various aberrations e.g., chromatic aberration
  • the present invention is also directed to a zoom lens whose number of constituent lenses is small, whose angle of view is large, which has a high zoom ratio and a high optical performance, and which is suitable for use with the lens retraction method, and to an image pickup apparatus having the zoom lens.
  • a zoom lens includes, in order from an object side to an image side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive refractive power, wherein an interval between the first lens unit and the second lens unit and an interval between the second lens unit and the third lens unit vary during zooming, wherein the first lens unit includes a composite optical element, wherein the composite optical element includes a lens element and a resin layer having an optical characteristic different from that of the lens element and laid on the lens element, and wherein a refractive power of the lens element ( ⁇ a ), an Abbe number of a material of the lens element with respect to d-line light ( ⁇ a ), a refractive power of the resin layer ( ⁇ b ), an Abbe number of a material of the resin layer with respect to d-line light ( ⁇ b ), and a focal length of the zoom lens at a wide-angle end (f w
  • a zoom lens includes, in order from an object side to an image side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive refractive power, wherein an interval between the first lens unit and the second lens unit and an interval between the second lens unit and the third lens unit vary during zooming, wherein the first lens unit includes a composite optical element, wherein the composite optical element includes a lens element made of a glass material and a resin layer having an optical characteristic different from that of the lens element and laid on the lens element, and wherein a focal length of the first lens unit (f 1 ), a focal length of the zoom lens at a wide-angle end (f w ), a radius of curvature of a surface of the composite optical element facing the object side (R 11 ), and a radius of curvature of a surface of the composite optical element facing the image side (R 12 ) satisfy the following conditions: 1.8 ⁇
  • FIG. 1 is a cross section of a zoom lens according to a first exemplary embodiment of the present invention.
  • FIGS. 2A and 2B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the first exemplary embodiment of the present invention.
  • FIG. 3 is a cross section of a zoom lens according to a second exemplary embodiment of the present invention.
  • FIGS. 4A and 4B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the second exemplary embodiment of the present invention.
  • FIG. 5 is a cross section of a zoom lens according to a third exemplary embodiment of the present invention.
  • FIGS. 6A and 6B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the third exemplary embodiment of the present invention.
  • FIG. 7 is a cross section of a zoom lens according to a fourth exemplary embodiment of the present invention.
  • FIGS. 8A and 8B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the fourth exemplary embodiment of the present invention.
  • FIG. 9 is a diagram illustrating components of an image pickup apparatus according to an exemplary embodiment of the present invention.
  • any specific values for example the zoom ratio and F number, should be interpreted to be illustrative only and nonlimiting. Thus, other examples of the exemplary embodiments could have different values.
  • FIG. 1 is a cross section of a zoom lens at a wide-angle end (a short focal length end) according to a first exemplary embodiment of the present invention.
  • FIG. 2A and FIG. 2B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end (a long focal length end) for the zoom lens according to the first exemplary embodiment of the present invention.
  • the first exemplary embodiment is directed to a zoom lens having a zoom ratio of about 3.9 and an aperture ratio ranging from about 2.9 to about 6.5.
  • FIG. 3 is a cross section of a zoom lens at a wide-angle end according to a second exemplary embodiment of the present invention.
  • FIG. 4A and FIG. 4B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the second exemplary embodiment of the present invention.
  • the second exemplary embodiment is directed to a zoom lens having a zoom ratio of about 3.9 and an aperture ratio ranging from about 2.9 to about 6.5.
  • FIG. 5 is a cross section of a zoom lens at a wide-angle end according to a third exemplary embodiment of the present invention.
  • FIG. 6A and FIG. 6B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the third exemplary embodiment of the present invention.
  • the third exemplary embodiment is directed to a zoom lens having a zoom ratio of about 3.8 and an aperture ratio ranging from about 2.9 to about 5.7.
  • FIG. 7 is a cross section of a zoom lens at a wide-angle end according to a fourth exemplary embodiment of the present invention.
  • FIG. 8A and FIG. 8B respectively illustrate an aberration chart at a wide-angle end and an aberration chart at a telephoto end for the zoom lens according to the fourth exemplary embodiment of the present invention.
  • the fourth exemplary embodiment is directed to a zoom lens having a zoom ratio of about 3.9 and an aperture ratio ranging from about 2.9 to about 6.5.
  • FIG. 9 is a schematic diagram illustrating components of a digital still camera (image pickup apparatus) including a zoom lens according to an exemplary embodiment of the present invention.
  • the zoom lens according to each exemplary embodiment can be a photographic lens system for use with an image pickup apparatus.
  • an object image is formed on an imaging plane of a solid-state image sensor (photoelectric conversion element), such as a charge-coupled device (CCD) sensor or a complementary metal-oxide semiconductor (CMOS) sensor.
  • a solid-state image sensor photoelectric conversion element
  • CCD charge-coupled device
  • CMOS complementary metal-oxide semiconductor
  • an object side front side
  • an image side back side
  • a zoom lens includes a first lens unit L 1 a - d having a negative refractive power (optical power: an inverse of a focal length), a second lens unit L 2 a - d having a positive refractive power, and a third lens unit L 3 a - d having a positive refractive power.
  • a first lens unit L 1 a - d having a negative refractive power (optical power: an inverse of a focal length)
  • second lens unit L 2 a - d having a positive refractive power
  • L 3 a - d having a positive refractive power
  • G denotes an optical block (glass block) that is equivalent to an optical filter, a face plate, a liquid crystal low-pass filter, an infrared-ray cut filter, or other type of optical filter as known by one of ordinary skill in the relevant arts.
  • IP denotes an image plane, for example, on which an imaging plane of a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or a CMOS sensor is positioned when the zoom lens is used as a photographic optical system for a video camera or a digital still camera.
  • d and g respectively denote d-line light (wavelength: 587.6 nm) and g-line light (wavelength: 435.8 nm).
  • ⁇ M and ⁇ S respectively denote a meridional image plane and a sagittal image plane.
  • Fno denotes an F number, and “ ⁇ ” denotes a semifield angle.
  • the Y-axis in the spherical aberration's graph is entrance pupil radius
  • the Y-axis in the astigmatism's and distortion's graphs is image height.
  • the “wide-angle end” and the “telephoto end” each refer to a zoom position of a lens unit for zooming (the second lens units L 2 a - d or the second and third lens units L 2 a - d and L 3 a - d ) is mechanically positioned on either of both ends of a range in which the lens unit can move along an optical axis.
  • the first lens unit L 1 a - d moves with a locus convex towards the image side (A 1 - 4 ), the second lens unit L 2 a - d moves monotonously towards the object side (B 1 - 4 ), and the third lens unit L 3 a - d moves monotonously towards the image side (C 1 - 4 ).
  • the lens units are moved to change the interval between the lens units.
  • focusing is performed by the third lens unit L 3 a , L 3 b , L 3 d.
  • focusing is performed by the first lens unit L 1 c.
  • the first lens unit L 1 a - d includes a composite optical element Gc 1 - 4 .
  • the composite optical element Gc 1 - 4 includes a lens element Ga 1 - 4 made of a glass material or a resin and having a negative refractive power and a resin layer Gb 1 - 4 having an optical characteristic different from that of the lens element Ga 1 - 4 and laid on the lens element Ga 1 - 4 .
  • the resin layer Gb 1 - 4 acts as a lens having a positive refractive power (acts to exert a refractive power).
  • At least one surface of the lens element Ga 1 - 4 is aspheric.
  • the lens element Ga 1 - 4 is formed by polishing a glass material or by molding a glass material.
  • At least one surface of the resin layer Gb 1 - 4 is aspheric.
  • various off-axis aberrations e.g., astigmatism and distortion occurring in the case where the zoom lens has a large aperture ratio, are effectively corrected or reduced by introducing an aspheric lens in the lens unit.
  • the lens element Ga 1 - 4 refers to an optical element (lens), such as a lens made of a glass material or a plastic material, which is a base plate having a surface on which a resin can be laid.
  • the resin layer Gb 1 - 4 which is laid on the lens element Ga 1 - 4 , can be previously molded as long as the resin layer Gb 1 - 4 has an optical characteristic different from that of the lens element Ga 1 - 4 .
  • the lens element Ga 1 - 4 is made of a glass material in terms of material stability in manufacturing.
  • the first lens unit L 1 a moves backward and forward with a locus convex towards the image side (A 1 ), the second lens unit L 2 a moves towards the object side (B 1 ), and the third lens unit L 3 a moves towards the image side (C 1 ).
  • the zoom lens according to the first exemplary embodiment performs zooming by moving (B 1 ) the second lens unit L 2 a .
  • the first lens unit L 1 a moves backward and forward (A 1 ) and the third lens unit L 3 a moves towards the image side (C 1 ) to compensate for the movement of an image point caused by the variation of magnification.
  • the first lens unit L 1 a having a negative refractive power includes a negative lens (lens element) Ga 1 whose both lens surfaces are concave and a resin layer Gb 1 laid on the image side surface of the negative lens Ga 1 .
  • the second lens unit L 2 a includes, in order from the object side to the image side, a cemented lens obtained by cementing a positive lens whose both lens surfaces are convex and a negative lens whose both lens surfaces are concave, and a cemented lens obtained by cementing a negative meniscus lens whose lens surface on the image side is concave and a positive meniscus lens whose lens surface on the object side is convex.
  • the third lens unit L 3 a includes a positive meniscus lens whose lens surface on the image side is convex.
  • the first lens unit L 1 b moves backward and forward with a locus convex towards the image side (A 2 ).
  • the second lens unit L 2 b moves towards the object side (B 2 ) and the third lens unit L 3 b moves towards the image side (C 2 ).
  • the second lens unit L 2 b moves (B 2 ) to perform zooming.
  • the first lens unit L 1 b moves backward and forward (A 2 ), and the third lens unit L 3 b moves towards the image side (C 2 ) to compensate for the movement of an image point caused by the variation of magnification.
  • the first lens unit L 1 b includes a negative lens (lens element Ga 2 ) whose both lens surfaces are concave and a resin layer Gb 2 laid on the image side surface of the negative lens Ga 2 .
  • the second lens unit L 2 b includes, in order from the object side to the image side, a positive lens whose both lens surfaces are convex, a negative lens whose both lens surfaces are concave, and a positive meniscus lens whose surface on the object side is convex.
  • the third lens unit L 3 b includes a positive lens whose both lens surfaces are convex.
  • the first lens unit L 1 c moves backward and forward with a locus convex towards the image side (A 3 ).
  • the second lens unit L 2 c moves towards the object side (B 3 ) and the third lens unit L 3 c moves towards the object side (C 3 ).
  • the second lens unit L 2 c and the third lens unit L 3 c move (B 3 and C 3 ) to perform zooming.
  • the first lens unit L 1 c moves backward and forward (A 3 ) to compensate for the movement of an image point caused by the variation of magnification.
  • the first lens unit L 1 c includes a negative lens (lens element) Ga 3 whose both lens surfaces are concave and a resin layer Gb 3 laid on the image side surface of the negative lens Ga 3 .
  • the second lens unit L 2 c includes, in order from the object side to the image side, a positive lens whose both lens surfaces are convex and a negative meniscus lens whose lens surface on the object side is convex.
  • the third lens unit L 3 c includes a positive lens whose both lens surfaces are convex.
  • the first lens unit L 1 d moves backward and forward with a locus convex towards the image side (A 4 ).
  • the second lens unit L 2 d moves towards the object side (B 4 ) and the third lens unit L 3 d moves towards the image side (C 4 ).
  • the second lens unit L 2 d moves (B 4 ) to perform zooming.
  • the first lens unit L 1 d moves backward and forward (A 4 ) and the third lens unit L 3 d moves towards the image side (C 4 ) to compensate for the movement of an image point caused by the variation of magnification.
  • the first lens unit L 1 d includes a negative lens (lens element) Ga 4 whose both lens surfaces are concave and a resin layer Gb 4 laid on the image side surface of the negative lens Ga 4 .
  • the second lens unit L 2 d includes, in order from the object side to the image side, a cemented lens obtained by cementing a positive lens whose both lens surfaces are convex and a negative lens whose both lens surfaces are concave, and a cemented lens obtained by cementing a negative meniscus lens whose lens surface on the image side is concave and a positive meniscus lens whose lens surface on the object side is convex.
  • the third lens unit L 3 d includes a positive meniscus lens whose lens surface on the image side is convex.
  • the first lens unit L 1 a - d includes the composite optical element Gc 1 - 4 .
  • the composite optical element Gc 1 - 4 includes the lens element (negative lens) Ga 1 - 4 and the resin layer Gb 1 - 4 laid on the lens element Ga 1 - 4 .
  • the resin layer Gb 1 - 4 is made of a resin curable by application of light or heat
  • the resin layer Gb 1 - 4 is generally produced by photo polymerization molding or thermal polymerization molding using a molding tool.
  • the thickness of the resin layer Gb 1 - 4 can easily be made thin. Accordingly, the entire optical system can be more easily downsized as compared to the case where the optical element is made of a glass material.
  • the surface of the resin layer Gb 1 - 4 (image side surface) opposite to a boundary surface between the lens element Ga 1 - 4 and the resin layer Gb 1 - 4 can be relatively easily made aspheric.
  • the surface of the lens element Ga 1 - 4 (object side surface) opposite to the boundary surface between the lens element Ga 1 - 4 and the resin layer Gb 1 - 4 has an aspheric shape.
  • the boundary surface between the lens element Ga 1 - 4 and the resin layer Gb 1 - 4 can have an aspheric shape.
  • the conditional expression (1) is concerned with achromatism between the lens element Ga 1 - 4 and the resin layer Gb 1 - 4 . If the upper limit of the conditional expression (1) is exceeded, achromatism cannot be effectively performed. Accordingly, in this case, it becomes difficult to appropriately correct chromatic aberration occurring with the first lens unit L 1 a - d , such as chromatic aberration of magnification at the wide-angle end and axial chromatic aberration at the telephoto end.
  • the conditional expression (2) is concerned with a ratio of focal length between the first lens unit L 1 a - d and the zoom lens.
  • conditional expression (3) is concerned with the shape of both refractive surfaces of the composite optical element Gc 1 - 4 (the lens element Ga 1 - 4 and the resin layer Gb 1 - 4 ) of the first lens unit L 1 a - d contacting the air.
  • conditional expression (4) is concerned with appropriately setting a thickness of the resin layer Gb 1 - 4 laid on the lens element Ga 1 - 4 .
  • the resin layer Gb 1 - 4 becomes too thin to obtain a sufficient positive refractive power to provide achromatism to the lens element Ga 1 - 4 , which exerts a main refractive power of the first lens unit L 1 a - d .
  • a desired effect of achromatism cannot be obtained.
  • the resin layer Gb 1 - 4 becomes too thick to obtain an effect of downsizing the first lens unit L 1 a - d and the entire zoom lens.
  • the composite optical element Gc 1 - 4 included in the first lens unit L 1 a - d having a negative refractive power includes the lens element Ga 1 - 4 and the resin layer Gb 1 - 4 . Both light-entrance and light-exit surfaces of the resin layer Gb 1 - 4 are refractive surfaces.
  • the resin layer Gb 1 - 4 has a positive refractive power as a whole.
  • the resin layer Gb 1 - 4 is made of an optical material having a high dispersion characteristic, thus improving the effect of correction of chromatic aberration.
  • the conditional expression (5) is concerned with appropriately setting an Abbe number ⁇ b of the resin layer Gb 1 - 4 with respect to d-line light.
  • the resin is not limited to this as long as the resin satisfies the conditional expression (5).
  • conditional expression (6) is concerned with the lens shape of the positive lens of the third lens unit L 3 a - d.
  • the positive refractive power of the positive lens on the object side becomes too strong to set off variation of aberration, such as field curvature, occurring at the first lens unit L 1 a - d during zooming.
  • the positive refractive power of the positive lens on the image side becomes very strong, and a large amount of variation of field curvature occurs during focusing from an infinitely distant object to a closest object.
  • the conditional expression (7) is concerned with a ratio of focal length between the third lens unit L 3 a - d and the zoom lens at the wide-angle end. If the lower limit of the conditional expression (7) is exceeded, the refractive power of the third lens unit L 3 a - d becomes very small, and thus a composite refractive power of the first lens unit L 1 a - d and the second lens unit L 2 a - d is required to be set strong. Accordingly, in this case, it becomes difficult to correct off-axis aberration, such as distortion and field curvature, at the wide-angle end.
  • the refractive power of the third lens unit L 3 a - d becomes very strong, and a large amount of variation of various aberrations related to a distance to an object occurs at the telephoto end.
  • distortion can be corrected with a known electrical aberration correction method, for example.
  • the range of the values in the conditional expressions (1) through (7) can be altered as follows: 0 ⁇
  • the components are set as described above to obtain a zoom lens useful in a photographing system using a solid-state image sensor.
  • a small-sized zoom lens having a small number of lenses, useful in a lens retraction type zoom lens, having a zoom ratio of about 3 to 4, capable of correcting or reducing various aberrations (e.g., chromatic aberration), and having a high optical performance can be obtained.
  • FIG. 9 An exemplary embodiment of a digital camera (image pickup apparatus) that uses a zoom lens according to each exemplary embodiment as a shooting optical system will be described below with reference to FIG. 9 .
  • the digital camera includes a digital camera body 20 and a shooting optical system 21 .
  • the shooting optical system 21 includes a zoom lens according to any of the first to the fourth exemplary embodiments described above.
  • the digital camera body 20 includes a solid-state image sensor (photoelectric conversion element) 22 , such as a charge-coupled device (CCD) sensor or a complementary metal-oxide semiconductor (CMOS) sensor, configured to receive light forming an object image via the shooting optical system 21 .
  • CMOS complementary metal-oxide semiconductor
  • the digital camera body 20 further includes a recording unit 23 configured to record an object image received by the solid-state image sensor 22 .
  • the digital camera body 20 further includes a viewfinder 24 configured to allow a user to observe an object image displayed on a display element (not shown).
  • the display element includes a liquid crystal display panel and displays an object image formed on the solid-state image sensor 22 .
  • a zoom lens according to an exemplary embodiment of the present invention applied to an image pickup apparatus, such as a digital camera, a small-sized image pickup apparatus having a high optical performance can be implemented.
  • Numerical examples 1 through 4 that respectively correspond to the first through the fourth exemplary embodiments will be set forth below.
  • i denotes the order of a surface from the object side
  • Ri denotes a radius of curvature of the i-th lens surface (an i-th surface)
  • Di denotes a lens thickness and an air interval between the i-th surface and the (i+1)th surface
  • Ni denotes a refractive index and an Abbe number of the i-th optical material with respect to d-line light
  • W denotes the wide-angle end
  • T stands for the telephoto end.
  • a glass member such as a face plate.
  • k denotes a conic coefficient
  • each of “A”, “B”, “C”, “D”, and “E” denote an aspheric coefficient.
  • x denotes a displacement from a surface vertex along the optical axis in a position at a height “h” from the optical axis
  • R denotes a paraxial radius of curvature.
  • e ⁇ 0X denotes “ ⁇ 10 ⁇ X ”.
  • f denotes the focal length
  • Fno denotes the F number
  • ⁇ denotes the semifield angle.

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JP2008129460A (ja) * 2006-11-22 2008-06-05 Olympus Imaging Corp ズーム光学系、及びそれを有する電子撮像装置
JP5424553B2 (ja) * 2007-03-12 2014-02-26 オリンパス株式会社 結像光学系及びそれを有する電子撮像装置
JP5097446B2 (ja) * 2007-05-29 2012-12-12 パナソニック株式会社 ズームレンズ系、撮像装置及びカメラ
JP5101168B2 (ja) * 2007-05-29 2012-12-19 パナソニック株式会社 ズームレンズ系、撮像装置及びカメラ
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JP5213169B2 (ja) * 2008-08-22 2013-06-19 オリンパスイメージング株式会社 ３群ズームレンズ及びそれを備えた撮像装置
US7646547B2 (en) 2007-10-12 2010-01-12 Olympus Imaging Corp. Three-unit zoom lens and image pickup apparatus equipped with same
JP2011022380A (ja) 2009-07-16 2011-02-03 Sony Corp ズームレンズ及び撮像装置
JP5499628B2 (ja) * 2009-10-27 2014-05-21 ソニー株式会社 ズームレンズ及び撮像装置
JP5669105B2 (ja) 2010-12-28 2015-02-12 パナソニックＩｐマネジメント株式会社 ズームレンズ系、撮像装置及びカメラ
JP2012150432A (ja) 2010-12-28 2012-08-09 Panasonic Corp ズームレンズ系、撮像装置及びカメラ
CN103620470B (zh) 2011-06-24 2015-12-09 富士胶片株式会社 变焦镜头和成像设备
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JP6436653B2 (ja) * 2014-06-02 2018-12-12 キヤノン株式会社 ズームレンズ及びそれを有する撮像装置

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